The present invention relates to a template for topstitching joined workpiece parts on a sewing machine, in which the template is automatically moved by a feeding mechanism along a predetermined contour with respect to the needle.
From a product literature specification sheet (Adler 961-23-4 Template sewing unit identification No. SpP 2371-m-0979-Ti-1-3) there is known such a template which has been applied for the run- or topstitching of small parts such as cuffs, flaps and similar workpieces. For producing such articles, at first the cut plies of material are joined together at their margins by a run-stitch, at which one of these plies is provided with so-called fullness. According to the above-mentioned specification sheet it is possible to simultaneously cut off excessive material as the topstitching is carried out. In the following procedure the runstitched article will be turned and pressed, for which the manually inverted part will be placed over a spreadable sword. Due to the fullness of the ply, the runstitch seam will be placed within the outside contour of the turned and stretched workpiece. In the following, the workpiece will be loaded into a press for fixing the final shape by applying pressure heat and moisture. After a short time of dwell in the press, the workpiece is ready to be topstitched, and this may be manually carried out or by the application of a template.
The described method for producing such articles additionally requires the process of workpiece press between the runstitch- and topstitch operation. Besides the high investment cost for such a press and cost for running such press, cost for the necessary style-depending swords arise.
In the German Patent DE-PS No. 20 53 635 (equivalent to U.S. Pat. No. 3,762,348) there is described a device for topstitching such small articles as cuffs or the like workpieces, at which no work step of workpiece pressing is required. The known device is equipped with a rotating worktable installed with a plurality of workpiece clamps and corresponding track elements so as to make possible an overlapped work method, at which loading, sewing and stacking is simultaneously accomplished. Although this device has a flexible construction as to process workpieces of different sizes, investment cost for style-dependent tools arise when a style change becomes necessary. Furthermore, the work for converting styles requires considerable time which gives the user the best benefit only with large quantities of workpieces to be processed.
Accordingly, it is a main object of the present invention to provide an inexpensive template which makes possible to topstitch small workpieces without the necessity of pressing the workpiece prior to topstitching.
It is a further object of the invention to provide a device for topstitching small workpieces, while incurring minimum of cost related to style changes.
Still another object of this invention is to install the template with adjustable stops to determine a firm relation of outside contour to the topstitch line of the workpiece.
Still another object of the present invention is to provide a device of the aforegoing character which is simple in construction and reliable in operation.